MOLLUSC A— GASTROPODA. 597 



e / . Expansion compound, posterior notch drawn out and adhering 

 to spire, sometimes covering it ; outer lip often much divided. 



CXXXVII. Aporrhais. 



17. Aperture with outer lip thickened, but not expanded 23*. 



23*. Anterior notch very slight, shell small, surface ribbed, rarely 



smooth CXVI. Rissoina 



23*. Anterior notch drawn out into short canal, inner lip reflexed. 



CXL. Kimella. 

 VIII. Shell short and thick 18. 



18. All whorls smooth and rounded, shell subglobose CXC. Ancillopsis. 



18. At least the younger whorls angulated or ornamented or both 24*. 



24*. Outer lip not denticulate P. 



f / . Surface with few strong fold-like spirals... CLXXXII. Ecphora. 



P. Surface smooth or with ribs and fine spirals 54. 



54. With distinct shoulder, angle strongly nodose, notch faint. 



CXXIX. Pyrgulifera. 



54. Without shoulders, whorls rounded, notch strong. 



CXLVII. Buccinum. 



24*. Outer lip denticulate or lirate g / . 



g / . Surface smooth or spiralled CXLVI. Columbella. 



g / . Surface with ribs and spirals 55. 



55. With strong columellar folds CXCI. Cancellaria. 



55. Columella without folds, rarely denticulate gg'. 



gg 7 . Canal short, deflected, often only notch-like. 



CLI. Nassa. 

 gg'. Canal longer, slightly bent or straight. 



CLXXVIII. Urosalpinx. 

 24*. Outer lip reflexed, inner lip expanded, anterior canal short, twisted 



and bent backwards CXLIV. Cassidaria. 



24*. Outer lip thickened, inner lip smooth. Anterior notch very slight. 



CXVI. Rissoina. 



VIII. Shell varying in form, with aperture as long as, or longer than, the length 



of the spire 19. 



19. Aperture without expanded lip 25*. 



25*. Shell fusiform and slender, drawn out anteriorly into more or less 



slender canal h / . 



h / . Spire high, about equal in length to aperture 56. 



56. Outer lip with notch or slit, often with slit band hh'. 



hi/. Canal long CXCIII. Pleurotoma. 



hh'. Canal short, less than half the length of shell i6f. 



i6f. Slit or notch at suture CXCV. Mangilia. 



l6f. Slit or notch below suture CXCIV. Drillia. 



56. Outer lip without notch or slit ii'. 



W . Columellar lip without folds 17-f-. 



17-f. Early whorls ribbed, last whorls smooth, often 



with sutural shelf CLXXII. Clavilithes. 



I7f. All whorls smooth or only with spirals, body 

 whorl strongly convex. 



CLXXVII. Mazzalina. 



17-f. All whorls ribbed or spiralled or both %. 



%. Ribs strong, aperture not abruptly contracted 



